In an interview two years ago, Paul McCartney was asked some chestnut of a question about the plight of the aging rock star. He replied thoughtfully and sympathetically, but without much concern for his own situation. He could see how worrisome it might be to grow long in the tooth and still pass oneself off as a teen angel, but he felt his own fans had stopped thinking of him that way. McCartney was confident that he'd successfully made the transition, in his audience's mind, from boyish sex symbol to full-grown family man.

With each new Wings LP, McCartney's tranquility and daddyhood have been further reinforced. Like James Taylor and Carly Simon, Paul and Linda McCartney have evolved into one of rock's first families — a process that's had less to do with scenes from either marriage than with the respect for stability, the feeling of being rooted and the intermingling of adult and childish sentiments that informs their music these days. Carly Simon's Boys in the Trees, with its sultriness and sophistication, might initially seem to share little common ground with Wings' breezy, determinedly whimsical London Town. But both records suggest a similar feeling of grateful, hopeful and also slightly cautious contentment, even if they do arrive at that juncture via vastly different routes.

Boys in the Trees is Carly Simon's most serene accomplishment to date, but its moods vary dramatically enough to indicate that peace of mind comes at a high price. Under the influence of producer Richard Perry, Simon could come on like gang busters, often very successfully. But Arif Mardin, working here with Simon for the first time, takes a different tack altogether. His production is more custom-tailored than Perry's and has the effect of bringing the singer into sharp focus while making her sound subtler than before, of streamlining her music by toning down its preciousness and its red-hot-mama aspect. Mardin's efforts are every bit as unobtrusive as they are strenuous: he's like one of those makeup magicians who spends six hours making a model look as if she's just scrubbed her face with a washcloth.

The scrubbed-down Simon is a mightily seductive creature and also a somewhat mocking one, but for once these elements are firmly controlled. "You Belong to Me," cowritten by Michael McDonald of the Doobie Brothers, greets an apparently errant lover with a playful wink and with the warm understanding that a couple's fear of losing one another can be a nice way of keeping everyone on his or her toes. It's a number that could easily have been belted out or growled à la "You're So Vain," but this time Simon prefers to sound more like a cat who's been dining on canary. Somehow, she's a lot more compelling using a gently chiding tone than she is striking a come-hither-or-else pose.

Inevitably, since they address themselves to the same subjects so often, Carly Simon's and James Taylor's individual albums tend to amplify one another. Simon's title song here, a contemplative ballad about revisiting the house and attitudes of her adolescence, is delivered in the same quietly disheartened mood Taylor evoked in "Another Grey Morning."

The album's most artful juxtaposition also involves Taylor, since Simon sings a song of his, "One Man Woman," with a funny, confidential, lily-white soulfulness reminiscent of her husband's manner. The song is full of raunch and boastfulness about conjugal fidelity, but it's swiftly followed by a slow waltz (by Simon and Jacob Brackman) designed to seduce a former lover. The pairing of the two numbers is especially poignant in its suggestion that if even the most energetic, well-intentioned love affair turns sour, there's always a second chance.

Boys in the Trees has a few holes, but there are no major craters — and for an artist as erratic as Simon once was, achieving this kind of consistency amounts to a major breakthrough. "De Bat (Fly in Me Face)" is evidence — in case any more were needed, after Taylor's "Traffic Jam" — that urbane, cosmopolitan white people sound silly singing jazz or calypso novelty songs. And "Haunting," with its overblown arrangement featuring harps and ghostly chorus, is a throwback to Carly Simon's more pretentious days. But for the most part, she's become quite a reliable songwriter, even at the cost of being repetitive ("Back Down to Earth" is a direct recycling of "Haven't Got Time for the Pain"). And the confidence and clarity of her delivery mesh beautifully with the mature intelligence that's at work in so much of her material.

London Town is so lighthearted that the album's feeling of familial strength and affection is virtually the only thing that binds it to earth. Paul and Linda McCartney and Denny Laine — who qualifies as an honorary Uncle Denny or something, since he's cowritten the two sweetest children's songs here — flit blithely from fairy tale to fairy tale, with virtually no notion that there's a real world out there, let alone a real audience. "Backwards Traveller," for instance, begins as a brilliant, jolting hard-rock number and ends a minute and seven seconds later, almost as if — no, exactly as if — nobody had the presence of mind to write or record the rest of it. Even the best songs here — and a couple of them, like "Deliver Your Children" and "Children Children," are just wonderful — sound as if Wings were only half trying.

McCartney has long since established himself as rock's answer to Peter Pan, and those tall-tale numbers in which he seems to be both a spellbinding grownup and an enraptured child have a very special tenderness. Another side of him, which began to rear its head in the playful defensiveness of "Silly Love Songs," turns up this time in "Famous Groupies," a dry, slightly bitchy song indicating that idle chatter about Linda McCartney still gets the family's goat. The blasting behind "I've Had Enough" and the incongruously good-humored "Don't Let It Bring You Down" also hint at a minor mean streak, one that spices up the Wheatena with a welcome note of discord.

McCartney, et al., can probably continue in the present vein indefinitely, retaining their enormous popularity and trailing a vapor of unmitigated niceness. But if Wings' familial harmony ever palls long enough to send everyone back to the drawing board, the group in general — and, of course, Paul McCartney in particular — may face an interesting dilemma. Francois Truffaut, widely beloved for the childlike wit and whimsy of most of his films, has begun to attempt more grave and reflective work lately, and some of his most avid fans now grumble about feeling surprised, disappointed, even betrayed. McCartney's following is in some ways similar, and should he ever grow ambitious enough to strive for anything weightier than good cheer, he may face the same sort of resistance.

For the time being, as even the genial effortlessness of London Town demonstrates, Paul McCartney has a lot more talent than he knows, or cares, what to do with. Even without a little luck, he can get away with whistling a happy tune, letting a smile be his umbrella and singin' in the rain.